1. Field of the Invention
The invention relates to a microwave oven having an oven muffle which can be closed off tight against microwaves and is connected to a high-frequency oscillator, a rotatable shaft which is brought through a metallic wall of the muffle, for instance of a recirculated-air blower, as well as a microwave seal provided in the area of the opening.
2. Description of the Prior Art
A microwave seal for a microwave oven in which a metallic disc is mounted on the drive shaft of a recirculated-air blower immediately outside the shaft opening in the corresponding oven wall, i.e., outside the cooking chamber is disclosed in German Published Non-Prosecuted Application No. 27 15 636. This disc is to prevent microwave energy from escaping from the cooking chamber through the shaft opening to the outside. It has been found in practice that such a simple gap is usually not sufficient to completely inhibit the escape of microwave energy, especially if the gap between the disc and the outside of the wall at the circumference of the disc is of uneven size, which is usually the case if the muffle wall is heated to a high temperature, but the disc remains relatively cool. The wall sheet has a tendency to warp because of the strong material stresses which occur due to the high temperature rise.